Preheat the oven to 350°F (175°C).
Heat olive oil in a large oven-safe skillet over medium-high heat.
Add diced onions and sauté for 2 to 3 minutes until softened.
Add Italian sausage and cook until browned and no pink remains, then drain excess grease.
Stir in Italian seasoning, onion powder, garlic powder, and black pepper.
Pour in marinara sauce and mix thoroughly to combine.
Add chopped bacon, pepperoni slices, and frozen ravioli, stirring until ravioli is evenly coated.
Sprinkle shredded mozzarella cheese evenly on top and add extra bacon and pepperoni if desired.
Cover skillet with foil and bake for 20 to 25 minutes until hot and bubbly.
Remove foil and broil on high for 2 to 3 minutes until cheese is golden and slightly crispy.
Allow the dish to cool slightly before serving warm.